An automobile employs various rotary machines such as a differential device and a power take-off unit. Some of these rotary machines often have clutches incorporated therein. In a lock-up differential for example, a clutch is incorporated for the purpose of limiting differential motion of the differential gear. Or, a purpose of controlling torque transmission to a power take-off unit or a free-running differential may necessitate incorporation of a clutch.
A clutch is, in a case of a dog clutch, comprised of a pair of clutch members each having clutch teeth. When one of them approaches the other, the clutch becomes connected. When they come apart, the clutch becomes disconnected. An actuator such as a hydraulic device or a solenoid is used to move the clutch member.
Japanese Patent Application Laid-open No. 2007-92990 discloses a related art.